Lactic acid bacteria, such as Lactobacillus and Lactococcus, and other Gram-positive bacteria such as Bifidobacterium, Leuconostoc and Streptococcus, are widely used for manufacturing food products and for the fermentation of raw agricultural products.
As these bacteria tend to be harmless and tend to remain viable in the intestinal environment, there is now interest in using these bacteria to produce heterogenous proteins (i.e. proteins that are not naturally produced by the bacteria), especially for use in manufacturing functional food products that provide beneficial health effects, and also in the manufacture of new bio-pharmaceutical products.
In view of these potential applications of lactic acid bacteria, there is a need for molecules that can be expressed on the cell surface of Gram-positive bacteria such as Lactobacillus, Lactococcus, Bifidobacterium, Leuconostoc and Streptococcus, or for example, in a culture supernatant derived from these bacteria. Further, there is a need for molecules that can be expressed in lactic acid bacteria together with a heterogenous protein in the form of a fusion protein.